DC Isolator Switch Manufacturer

PV, ESS, EV charging, telecom & industrial DC isolation up to 1500 VDC

A DC isolator switch—also called a DC isolation switch, DC disconnect switch, or DC switch-disconnector—provides a visible, lockable means of isolation so technicians can safely maintain PV arrays, inverters, battery racks, EV chargers, telecom rectifiers, and DC drives. Unlike over-current protective devices (OCPD) such as DC circuit breakers and DC fuses, the isolator’s job is to manually make/break under load (where applicable) and securely isolate the circuit. In PV plants and energy storage systems, a correctly selected DC isolator works alongside OCPD and DC SPDs to form a complete protection and maintenance scheme.

Product Portfolio (what we build)

DIN-rail DC isolators for string/array/inverter DC input, 600/1000/1500 VDC, 1–4 poles, 16–320 A
Weatherproof rooftop PV DC isolators (IP66/IP65) with padlockable red/yellow rotary handles, UV-stable enclosures
Enclosed DC disconnect switches for battery energy storage (ESS) and EV charger cabinets, up to 1500 VDC and high DC currents
Multi-string DC isolators (2-string / 4-string) for combiner boxes; +/–/PE markings and polarity labels
Accessories: door-interlock shafts, defeatable interlocks, auxiliary contacts, mechanical key interlocks, handle extensions, shrouded terminals

How a DC Isolator Works (and what makes it “DC-ready”)

Double-break, knife-blade or bridge contacts increase opening gap and improve DC arc extinction.
Arc-chute & magnetic blow-out geometry drives the arc into splitter plates to cool and lengthen it (DC has no natural current zero).
Silver-alloy contact tips reduce resistance and erosion; pressure springs maintain contact force over life.
Switch-disconnector vs. isolator: an on-load switch-disconnector is tested to make/break rated current; a pure “off-load isolator” is for isolation only (choose based on your needs).
Padlockable rotary handles provide clear OFF position, visible isolation, and LOTO compliance for field safety.

Selection Guide (long-tail best practices)

System voltage (VDC): choose isolators rated for 1000 VDC or 1500 VDC as required; for very high voltages, use series-pole wiring per the datasheet.
Current & utilization category: size to operating current with headroom. For DC loads use utilization categories from IEC 60947-3 (e.g., DC-21/22/23 A/B) that match your duty (resistive, mixed, motor).
Number of poles: PV strings typically need 2-pole ( + and – ); grounded arrays may need +/– to PE isolation strategy at the inverter input—follow inverter/PV instructions.
Environment & enclosure: rooftop PV needs IP66 UV-stable isolators; indoor cabinets can use DIN-rail or enclosed IP20/IP54 models. Check ambient temperature and derating.
Handle & interlock options: lockable red/yellow handle for LOTO, door-interlock on MCC/inverter cabinets, defeatable options for commissioning.
Coordination with OCPD: isolators do not provide short-circuit protection—coordinate with DC fuses or DC breakers for SCCR.
PV compliance & placement: array-side and inverter-side DC isolators are commonly required; follow PV installation rules and inverter manuals (e.g., “PV DC disconnector at inverter DC input”).
Marking & labels: use clear “PV DC ISOLATOR” labels, polarity arrows, string IDs, torque specs, and wiring diagrams inside the lid.

Installation Tips (reduce risk & arc stress)

Keep conductors short and straight; avoid loops; torque lugs to spec; use correct cable glands and gaskets.
Respect line/load orientation if specified; verify polarity.
Mount close to the equipment (inverter DC input / combiner box / battery rack) for effective isolation.
On rooftops, use IP66 isolators with UV-stable housings; seal entries to maintain rating.
For ESS battery disconnects, place the isolator where maintenance staff can access it quickly and lock it safely.

Testing & Compliance (standards you’ll see on the label)

IEC 60947-3 — switches, disconnectors, switch-disconnectors, and fuse-combination units up to 1500 VDC (PV-specific clauses included in the latest consolidated version). IEC Webstore oc-api.iec.ch
IEC 60947-1 — general rules for low-voltage switchgear and controlgear (definitions, characteristics, safety). IEC Webstore http://IEC Webstoreoc-api.iec.ch
IEC 60364-7-712 — PV electrical installations (selection & application of PV DC isolators in the installation). IEC Webstore+1
UL 98 / UL 98A / UL 98B — enclosed/dead-front and open-type switches; PV-specific outlines cover photovoltaic switches used in North America. standardscatalog.ul.com+1 UL Solutions+1

Authoritative external resources (DoFollow):
IEC 60947-3: https://webstore.iec.ch/en/publication/107159
IEC 60947-1: https://webstore.iec.ch/en/publication/26973
IEC 60364-7-712: https://webstore.iec.ch/en/publication/28213
UL 98: https://standardscatalog.ul.com/ProductDetail.aspx?productId=UL98
UL PV switch info (98A/98B): https://www.ul.com/services/switch-certification-and-evaluation-services

Quality & Manufacturing (what we control)

CNC-machined current paths, silver-tipped contacts; calibrated springs for stable contact force
Arc-chute design & magnet placement validated by DC interruption tests
End-of-line inspections: dielectric, insulation resistance, contact resistance, mechanical endurance, handle/shaft integrity
Traceability: QR/lot IDs, RoHS/REACH documentation, DFMEA/PFMEA & SPC on critical dimensions

Applications (long-tail coverage)

Rooftop solar DC isolator IP66 with lockable rotary handle
1500 VDC isolator switch for utility-scale PV string/array and central/hybrid inverters
Battery DC disconnect switch for ESS racks and DC busbars
EV charger maintenance disconnect inside DC fast-charging cabinets
Telecom −48 V DC isolation switch for rectifier/distribution panels
Industrial DC drive isolator and combiner box DC switch-disconnector

Why work with a custom DC isolator switch manufacturer

Ratings tailored to your topology: 600/1000/1500 VDC, 16–320 A, DC-21/22/23 categories

Padlockable, red/yellow handles, door-interlocks, and auxiliary signaling contacts
IP66 weatherproof rooftop enclosures and DIN-rail cabinet versions
Clear coordination with DC SPDs and OCPD for code compliance
Fast lead time, OEM branding, custom labels & documentation packs

Request a custom quote

Send your VDC, current, utilization category, number of poles, enclosure rating (e.g., IP66), handle/interlock needs, installation location (rooftop/inverter input/combiner/ESS), and any OCPD/SPD coordination requirements.

FAQs

Q1. What’s the difference between a DC isolator and a DC switch-disconnector?

A pure isolator provides safe isolation in the OFF position; a switch-disconnector is tested to make/break load current as well, which many PV/ESS applications require.

Q2. Do I need a 2-pole or 4-pole DC isolator for PV strings?

Most strings use 2-pole (+ and −). Multi-MPPT inverters or special grounding schemes may require more poles—follow the inverter manual.

Q3. Can a DC isolator replace a circuit breaker or fuse?

No. It’s not an over-current device. Coordinate with DC breakers or DC fuses for short-circuit protection.

Q4. What do DC-21 / DC-22 / DC-23 mean?

They’re utilization categories from IEC 60947-3 indicating the duty (resistive, mixed, motor). Choose the category that matches your load type.

Q5. When should I specify IP66 weatherproof isolators?

Use IP66 (or higher) for rooftop PV and exposed outdoor sites; indoor cabinets usually use DIN-rail or enclosed IP20/IP54 units.

Q6. How do I size current and voltage for a 1500 V PV array?

Select an isolator rated for 1500 VDC and sized for array current with margin. For very high VDC, use series-pole wiring if specified.

Q7. Are DC isolators polarized?

Many are polarity-sensitive and marked + / −. Follow the wiring diagram to ensure proper arc control and contact separation.

Q8. Where should PV DC isolators be installed?

Typically at the inverter DC input and often at array/combiner level. Keep the device accessible and clearly labeled.

Q9. What maintenance is recommended?

Periodic visual checks, handle operation, terminal re-torque to spec, and inspection for discoloration or ingress. Replace if damage or overheating is observed.

Q10. Can I lock the isolator OFF for LOTO?

Yes—choose models with padlockable red/yellow rotary handles and door interlocks to support lock-out/tag-out procedures.

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